This invention relates to wheel and bearing systems for load transporting overhead trolley assemblies having a load support bracket with opposed stems axially mounting laterally offset wheels in rolling engagement with an overhead track having horizontally inclined wheel support surfaces. In typical manufacturing plants, such overhead trolleys conveyors transport very heavy loads often measured in tons and are subjected to heavy stresses and strains. The overhead track typically is a heavy gauge steel I beam and the trolley parts inclusive of the wheel and bearing systems, are typically formed of non-compressible, non-resilient rugged steel parts. In addition to strength requirements, some of the other considerations recognized by the present invention are the need to control the considerable wear which results over time with use, and the need for wheel bearing componetry which can be easily and economically manufactured and assembled with precision.